{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,21]],"date-time":"2026-07-21T03:07:53Z","timestamp":1784603273929,"version":"3.55.0"},"reference-count":35,"publisher":"Wiley","issue":"5","license":[{"start":{"date-parts":[[2026,4,12]],"date-time":"2026-04-12T00:00:00Z","timestamp":1775952000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,4,12]],"date-time":"2026-04-12T00:00:00Z","timestamp":1775952000000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"funder":[{"DOI":"10.13039\/100014653","name":"Manchester Biomedical Research Centre","doi-asserted-by":"publisher","award":["NIHR203308"],"award-info":[{"award-number":["NIHR203308"]}],"id":[{"id":"10.13039\/100014653","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Intl Journal of Cancer"],"published-print":{"date-parts":[[2026,9,1]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:p>Adult weight gain (AWG) increases postmenopausal breast cancer risk, whereas an early first pregnancy (FP) is protective. As pregnancy is a key contributor to weight gain, we investigated a potential interaction effect between these two factors on BC risk. We analysed prospective data from 48,417 women in the Predicting Risk of Breast Cancer at Screening (PROCAS) cohort (recruited 2009\u20132015). A Cox proportional hazards model was used to test for an interaction between first pregnancy age and weight gain on breast cancer risk. After a median follow\u2010up of 6.4\u2009years, 1702 incident breast cancers were identified. Compared to women with an early FP (&lt;\u200930\u2009years) and stable weight (\u2264\u20095%), risk was highest among those with substantial AWG (&gt;\u200930%) combined with a late FP (\u2265\u200930\u2009years) (HR: 2.48, 95% CI: 1.82\u20133.37) or nulliparity (HR: 2.38, 95% CI: 1.74\u20133.27). Elevated risk was observed even with moderate weight gain (5%\u201315%). A non\u2010significant positive trend toward an additive interaction was observed for late FP (Relative Excess Risk due to Interaction (RERI): 0.32), whereas the risk in nulliparous women appeared independent of weight gain (RERI: \u22120.05). Maintaining a stable adult weight and an early first pregnancy are independently associated with a lower breast cancer risk. However, adult weight gain remains a significant risk factor regardless of reproductive history. The combination of high weight gain and late or no pregnancy identifies a high\u2010risk group who could be prioritized for weight\u2010management interventions in cancer prevention settings.<\/jats:p>","DOI":"10.1002\/ijc.70489","type":"journal-article","created":{"date-parts":[[2026,4,13]],"date-time":"2026-04-13T03:50:49Z","timestamp":1776052249000},"page":"1228-1239","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Age at First Pregnancy, Adult Weight Gain and Postmenopausal Breast Cancer Risk: The\n                    <scp>PROCAS<\/scp>\n                    Study\u00a0(United Kingdom)"],"prefix":"10.1002","volume":"159","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8237-5329","authenticated-orcid":false,"given":"Lee","family":"Malcomson","sequence":"first","affiliation":[{"name":"Division of Cancer Sciences, Faculty of Biology, Medicine and Health University of Manchester  Manchester UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6327-4357","authenticated-orcid":false,"given":"Adam","family":"Brentnall","sequence":"additional","affiliation":[{"name":"Wolfson Institute of Population Health Queen Mary University of London  London UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andrew G.","family":"Renehan","sequence":"additional","affiliation":[{"name":"Division of Cancer Sciences, Faculty of Biology, Medicine and Health University of Manchester  Manchester UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mary","family":"Pegington","sequence":"additional","affiliation":[{"name":"Division of Cancer Sciences, Faculty of Biology, Medicine and Health University of Manchester  Manchester UK"},{"name":"Nightingale Breast Screening Centre &amp; the Prevent Breast Cancer Research Unit Manchester University NHS FT  Manchester UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Elaine F.","family":"Harkness","sequence":"additional","affiliation":[{"name":"Nightingale Breast Screening Centre &amp; the Prevent Breast Cancer Research Unit Manchester University NHS FT  Manchester UK"},{"name":"Division of Informatics, Imaging and Data Sciences, Faculty of Biology, Medicine and Health University of Manchester  Manchester UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jake","family":"Southworth","sequence":"additional","affiliation":[{"name":"Nightingale Breast Screening Centre &amp; the Prevent Breast Cancer Research Unit Manchester University NHS FT  Manchester UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"D. Gareth","family":"Evans","sequence":"additional","affiliation":[{"name":"Nightingale Breast Screening Centre &amp; the Prevent Breast Cancer Research Unit Manchester University NHS FT  Manchester UK"},{"name":"Division of Evolution, Infection and Genomics, Faculty of Biology Medicine and Health University of Manchester  Manchester UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michelle","family":"Harvie","sequence":"additional","affiliation":[{"name":"Division of Cancer Sciences, Faculty of Biology, Medicine and Health University of Manchester  Manchester UK"},{"name":"Nightingale Breast Screening Centre &amp; the Prevent Breast Cancer Research Unit Manchester University NHS FT  Manchester UK"},{"name":"Manchester Academic Health Science Centre  Manchester UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,4,12]]},"reference":[{"key":"e_1_2_12_2_1","unstructured":"Cancer Research UK \u201cBreast Cancer Incidence (Invasive) Statistics 2020\u201d https:\/\/www.cancerresearchuk.org\/health\u2010professional\/cancer\u2010statistics\/statistics\u2010by\u2010cancer\u2010type\/breast\u2010cancer\/incidence\u2010invasive#ref\u20102."},{"key":"e_1_2_12_3_1","volume-title":"Diet, Nutrition, Physical Activity and Cancer: A Global Perspective","author":"World Cancer Research Fund\/American Institute for Cancer Research","year":"2018"},{"key":"e_1_2_12_4_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.ctrv.2016.07.006"},{"key":"e_1_2_12_5_1","doi-asserted-by":"publisher","DOI":"10.1111\/obr.13002"},{"key":"e_1_2_12_6_1","doi-asserted-by":"publisher","DOI":"10.1038\/ijo.2017.78"},{"key":"e_1_2_12_7_1","doi-asserted-by":"publisher","DOI":"10.1097\/AOG.0000000000000565"},{"key":"e_1_2_12_8_1","volume-title":"in Health Survey for England, 2021","author":"Digital NHS","year":"2022"},{"key":"e_1_2_12_9_1","unstructured":"ONS U \u201cBirth statistics: England and Wales 2023\u201d https:\/\/www.ons.gov.uk\/peoplepopulationandcommunity\/birthsdeathsandmarriages\/livebirths\/bulletins\/birthsummarytablesenglandandwales\/2022."},{"key":"e_1_2_12_10_1","volume-title":"Programme Grants for Applied Research. 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